Lectures are an effective teaching method because they exploit human evolved 'human nature' to improve learning

Bruce G Charlton

Abstract

Lectures are probably the best teaching method in many circumstances and for many students; especially for communicating conceptual knowledge, and where there is a significant knowledge gap between lecturer and audience. However, the lack of a convincing rationale has been a factor in under-estimating the importance of lectures and there are many who advocate their replacement with written communications or electronic media. But I suggest that lectures are effective because they exploit the spontaneous human aptitude for spoken (rather than written) communications and because they are real-time, human-presence social events (rather than electronic media). Literacy is a recently cultural artefact and for most of their evolutionary history humans spontaneously communicated information by speech. By contrast with speech, all communication technologies – whether reading a book or a computer monitor – are artificial and unnatural. This is probably why many people find it easier to learn from lectures than from media; and why excessive or inappropriate use of visual aids can so easily detract from the educational experience. The second reason for lectures’ effectiveness is that they are formally-structured social events which artificially manipulate human psychology. A formal lecture is a mutually-beneficial 'collusion' between class and lecturer. to improve learning. Lectures are delivered by an actually-present individual, and this creates a here-and-now social situation which makes lectures easier to attend to. The formal structure of a lecture therefore artificially focuses attention and generates authority for the lecturer to make their communications more memorable. Furthermore, to allow the potential for repeated interactions to allow trust to develop between lecturer and class, it is much more educationally-effective for lectures to be given as a course rather than as one-off interactions.

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Despite the lecture method being so unpopular among professional educational advisers, reformers and intellectuals generally - and almost annual declarations that information technology will render lectures obsolete - many scientists continue to give lectures and students continue voluntarily to attend them. This fact that lectures have survived so much official opprobrium suggests that they are a much more effective teaching method than they are given credit for. Indeed, my experience suggests that properly structured-lectures may be the best teaching method for many subjects and many students, and lectures may be especially well-suited to the transmission of conceptual and systematic knowledge. Lectures are therefore usually the best medium for teaching science up to the point where the student begins to specialize and train as a practicing scientist, at which point a more individualized and skill-orientated 'apprenticeship' becomes necessary.
In itself, the greater ease of learning from lectures may indeed account for some of the disdain with which many intellectuals regard lectures – since intellectuals are experts at the cognitively-challenging business of learning by solitary reading. For example, intellectuals may deride clear, comprehensible and enjoyable lectures as ‘spoon-feeding’ students; with the implication that students should be forced to work hard for their basic knowledge in the same way that intellectuals do for their advanced knowledge. Lectures are also criticized as inculcating a ‘passive’ attitude to learning. But we need to be clearer that making learning easier is an admirable objective, assuming that what is being learned is worthwhile (as it is in the sciences). Making learning easier is especially important for the less-naturally-gifted proportion of the population who make up an increasingly large number of higher education students in advanced societies due to the massive recent and continuing expansion of colleges and universities. If knowledge is valuable, then we should embrace effective methods of inculcating knowledge: the easier the better.

What follows are a series of personal impressions based upon 18 years of lecturing in universities and studying educational methods. I see many advantages to lectures, which seem obvious yet are seldom noted or acted-upon. The first is that it is easier for most people to learn conceptual information from spoken communications than from reading. The second is that the real-time, human-presence, social context of a formal lecture makes it easier for most students to focus attention and remember what is said than when students are required to work alone. A third factor which deserves recognition is that the proper unit of educationally-valuable lectures is a course of lectures, not a one-off talk. One-off talks may be entertaining (for the audience) and useful self-advertisement (for the lecturer) – but they do not have much to do with serious education.

In what follows I suggest that lectures are 'spontaneously' easier to learn-from than are written or electronic media, and the reason is probably that they exploit evolved human psychology. In other words, lectures are better suited to ‘human nature’ than solitary study from texts. There is a natural tendency for humans to learn by hearing and in social situations because this is the medium and context in which human ancestors (hunter-gatherers) did most of their learning. However, learning by solitary reading or from electronic media are a modern cultural artefacts, skills that must themselves be learned; they are not universal and require more effort. While some people manage reach a stage of cognitive development where they can self-educate from impersonal media, many people require a human situation and benefit from being part of a class being lectured by a real person.

The effectiveness of lectures

The lack of an accepted rationale for the method seems to make people guilty about using lectures. At best they are taken for granted (but without any attempts to understand or improve them), at worst attempts are made to replace lectures almost anything else; even when alternatives involving small-group teaching, seminars, or tutorials are completely impractical and unaffordable in mass higher education systems. Even absurd gestures such as abandoning real teaching altogether and getting groups of students to ‘teach-themselves’ is regarded by some educationalists as an improvement on lectures.

But perhaps the most convincing evidence of lectures’ effectiveness comes from what people actually do, rather than what people say, because expressed-opinions have few costs or consequences are therefore are a less reliable guide to preferences than lived-choices. I find it highly significant that lectures are especially used in teaching the most quantitative and systematic sciences, and for intensive professional training courses such as medicine, engineering and law – lectures are less used (and less prestigious) in the arts and humanities such as literature and philosophy. In other words, lectures are a focus of teaching in exactly the situations where transmission of knowledge is most vital, and in subjects where learning is most easily and validly measurable. Of course, lectures will only get you so far, and individual teaching by ‘apprenticeship’ supported by self-directed study remain necessary for learning specialized and high level skills.

It is striking that, despite increasing choice of alternatives, the great majority of students continue to enrol in attendance-based and residential universities where lectures are a primary mode of instruction. And, when at university, they usually show-up for lectures, even when the lectures are not compulsory, and even when written hand-outs or transcriptions are available. (However, I believe that written material too closely-keyed into the specific lecture content probably has a tendency to undermine the effectiveness of lectures – see below).

Students still choose lecture-based teaching despite the ready availability of cheaper and more convenient alternative qualifications from highly-reputable 'distance learning' institutions which have grown-up to exploit new communication technologies as they were invented. Postal correspondence courses were popular from the early twentieth century. The UK Open University added TV and radio broadcasting to the postal system. More recently, the massive and expanding University of Phoenix in the USA has used e-mail and internet technologies. But although distance-learning is often both high in quality and reasonable in price, it has added to, rather than displaced, the demand for attendance-based, lecture-focused educational institutions. Apparently, many students experience difficulties in learning in solitude even from the finest written or audio-visual media.

Taking all these observations together, there seems to be ample prima facie evidence that lectures are probably the best practicable teaching method in many circumstances and for many students. However, it is not generally understood why lectures are useful, and the lack of a convincing rationale for lectures has been a major factor in under-estimating their importance. Because this rationale is not understood, the conduct of lectures has often been changed in ways that make them less effective – for instance inappropriate use of visual aids, and undermining the focus upon spoken lectures by excessive emphasis on written support material (eg. hand-outs and transcripts – nowadays often distributed by the internet).

Lectures are essentially spoken

The specific reasons for the effectiveness of lectures which I wish to highlight here, are that they are essentially a form of spoken communication which is delivered to an audience by an actually-present and visible person. A lecture therefore constitutes a formally-structured social event which fits human nature and artificially manipulates human psychology to improve learning. Furthermore, educational lectures are given in ‘courses’ (not one-off lectures), which enable the audience to develop a relationship of trust with the lecturer.

It is easy for educated people in advanced societies to forget that literacy and solitude are both relatively-recent cultural artefacts. In the hunter-gatherer societies in which our (neuro-anatomically identical) ancestors dwelled for many tens of thousands of years, information was communicated mainly by direct speech and individuals were almost never alone; on the contrary being continually surrounded by people they knew very well. By contrast all communication technologies – whether reading a book, audio-visual media, or a computer monitor – are artificial and contrived and studying alone is a difficult skill with widely varying levels of attainment. This is probably the major reason why so many people find it easier to learn from a spoken lecture and in groups rather than alone.

But attending a course of lectures requires a long term commitment to be in the necessary place at the proper time. If you are not present and listening, you will not obtain the advantage of attending a lecture and will have to make-do with solitary personal study. Students may miss lectures through no fault of their own, as well as for less admirable reasons. This is undeniably inconvenient, but it is intrinsic to the medium. Only if the lectures are sub-optimal can students miss them without incurring some disadvantage.

Therefore, when a lecture course is the focus of teaching care should be taken not to sacrifice the essence of lectures by confusing students over the core learning activity which is expected of them. In lecture based course, students should understand that one major expectation is that they are required to attend lectures. Because the main medium of communication in a lecture is the spoken word, what is spoken should be regarded as the essence. The only way to make lecture attendance unimportant to learning is to diminish the effectiveness of the lecture to the point that the lecture is so mediocre that it makes little difference whether students have experienced it or not.

It is tempting to try and ameliorate the disadvantages to students who cannot, or prefer not to, attend lectures; by providing identical or more-detailed material as handout – perhaps distributed by the internet. Once handouts are established, it is tempting to distribute them in advance of spoken lectures. But both of these temptations should be resisted. In order to make the most of their natural strengths, lectures need to maintain their proper focus on speaking as the primary form of communication.

The primacy of the spoken word may explain my strong impression that ‘lecture notes’ are a much more effective way of recording information than texts (such as hand-outs) which have been prepared by the lecturer. This is because lecture notes recognize the primacy of the spoken word. A students’ own written summary of a lecture they have heard also seems to be more readily remembered than hand-outs. One important factor is that lecture note-taking has the advantage of encouraging 'deep processing' forms of memorizing, by imposing a need for students to understand, abbreviate and re-structure the information in the course of recording it. Indeed, it is the taking of lecture notes which is a key factor in converting the potentially-passive experience of listening to a lecture into the active experience of learning from a lecture.

Lecture notes also avoid the undermining effect of hand-outs. It is hard to exaggerate the extent to which hand-outs can damage the effectiveness of a lecture. A lecture is compelling in part because it is here-and-now, the student must concentrate, listen, understand – and these activities cannot be put off until later. The intensity of a lecture depends on this necessity for the student to focus. The student must record the lecture in their notes, and they must do it now – lecture notes cannot be put off until later. But the existence of hand-outs or transcriptions usurps this evanescent reality by imposing an unchanging abstraction. A handout stands-between the student and the real-time lecture in the same way that a video-camera stands between a tourist and landscape they are standing in. To see a lecture through the lens of a hand-out is as impoverished a perspective as seeing the Alps through the viewfinder of a camera.

Lecture notes therefore do not support lectures so much as interfere with them – and ‘interference’ is a fairly precise term for the interaction of two similar phenomena to the disadvantage of both. Interference can best be avoided when the written material that supports a lecture is differently-structured from the lecture itself. For example, reading a good textbook after a lecture should be not just reinforce the same facts in the same order, nor even just add some extra facts, but should offer a significantly different structuring of the facts. In this case, the written material will deepen the knowledge obtained from lectures without damaging the here-and-now focus or memorability of lectures.

There are several other several implications. Lecture teaching methods should not allow verbal information to become subordinated to ‘visual aids’, although it is another temptation to ‘spice up’ the lecture with attention-grabbing graphics. The primary visual aid should the lecturer him- or her-self, especially the lecturers face, in particular the lecturers eye contact. A lecture which takes place in the dark, where a disembodied voice intones sentences while slides are shown, can hardly be described as a lecture at all because it lacks the basis of a social event. A slide-based lecture in the dark is more like visiting the cinema. Indeed, unless carefully used, technological visual aids can be a significant distraction from the conceptual basis of a lecture.

My feeling is that, on the whole, it is best for lecturers to avoid complex visual material, unless this is unavoidable; because although impressive visuals are often entertaining, they are also usually distracting, and may undermine the educational purpose. For example, audio-visual material (TV, video, animations etc) are such compelling stimuli that they can easily break the conceptual thread of spoken discourse. Switching back and forth between audio-visual technology and the spoken voice involves a cognitive change of gear which is hard for students to accomplish.

In this respect, public lectures and television documentaries are a bad model. This is because these one-off presentations are not trying to educate their audience except in the most vague and general sense – in fact they are mainly trying to grab and hold the audience’s attention. A one-off lecture is an end in itself: the audience is not expected to understand or remember what has been said.

But an educational lecture is a means to an end, which is learning, and methods to attracts and sustain audience attention should be subordinated to that over-arching educational imperative.

Lectures as social events

As well as being spoken communications, lectures are properly delivered by an actually-present individual. This creates a here-and-now social situation which unfolds in real time. Humans are social animals, who are naturally more alert and vigilant in social situations.

What makes the lecture a social situation is the potential for two-way communication - mainly a visual link of eye-contact between lecturer and audience. This situation of social communication is what makes lectures easier to attend and remember than written material, because failure to pay attention or an apparent failure to comprehend material can be seen by the lecturer. This need for direct communication sets a size limit to effective lectures (although this size can be increased by good design of auditoria).

In a very large lecture auditorium – even more so when electronic media are used to transmit a lecture remotely - the lecturer cannot maintain eye-contact with all members of the audience. This has two bad effects: firstly that the lecturer cannot monitor the response to his words on the whole audience, secondly (and more importantly) that remote parts of the classroom become cut-off from the lecturer because the students instinctively recognize that they are not being visually monitored. The remote students lose the possibility of participating in the here-and-now social event, in effect they are excluded from the lecture situation.

A properly-conducted lecture also exploits another spontaneous psychological disposition: the tendency to attend to persons of authority. In effect, the formal lecture is a mutually beneficial 'collusion' between class and lecturer. The structure of a lecture creates a situation in which a group’s attention is focused on the lecturer. This artificially generates authority in the lecturer which creates a receptive psychological state conducive to learning. The collusion is that a class of students implicitly, by their silent attention, awards temporary authority to the lecturer (authority which happens to be gratifying for the lecturer) for the purpose of making learning more effective (which is gratifying for the students – and is the aim of the exercise).

To enable lectures to be effective for learning, the process of communication therefore needs to be controlled by the lecturer. If communications from the audience are too frequent or uncontrolled, for example too many questions or discussions interrupting the flow of discourse, then this will sabotage the necessary authority structure in a way that will undermine learning. ‘Hecklers’ understand this very well.

A further aspect is that my experience strongly suggests that lectures should where possible be given as a whole course – not as one-off events – and by a single lecturer – rather than by a team. This seems to work better because it needs repeated interactions for a relationship of trust to build up between lecturer and class – and only when trust is established (if it is established) will students learn effectively.

It is precisely because the authority structure of a formal lecture is so powerful and instrument for focusing attention and improving learning that the lecture medium can be abused for propaganda purposes. Because they so effectively exploit human psychology, lectures are intrinsically a form of imposition by one upon the many, and there need to be safeguards to prevent this situation being used for inappropriate purposes.

Conclusion

Scientists, who usually have something to teach which is worth learning, should feel more confident about the value of lecturing and the appropriateness of the method. Students are not being fobbed-off with an inferior medium when lectures are the focus of teaching, nor should the spoken lecture be seen as secondary to the provision of written handouts or transcripts.

Consequently lecturers should resist the temptation to make lecturers more ‘entertaining’ by over-using ‘visual aids’. Since lectures are primarily ‘aural’, the visual material should generally be appropriate for recording in lecture notes – which usually means simple summary diagrams. In general, lectures should aim to be enjoyable, but should not strive to be entertaining as the major goal; because lectures should be memorable rather than diverting.

In a nutshell, lectures retain a major educational role because they exploit evolved aspects of human nature to make learning easier and more effective when compared with electronic and literacy-based media. And, as university teaching continues to expand, it is important to make learning as easy as possible.

Instead of trying to phase-out lectures, we should strive to make them better. To do this entails understanding how lectures exploit human psychology - especially the fact that lectures are essentially formal, spoken, social events.